This invention deals generally with the distribution of particulate materials, e.g. granules and powders, and more specifically with a system for loading light particulate materials into several geometrically associated openings within one or more containers.
Loading of particulate material, which is alternatively referred to herein as granular material, into railcars or trucks is generally a slow process. Historically, plastic particulate material has been loaded into railroad cars and trucks by gravity. This requires elevating storage silos to allow for clearance for gravity flow, and the structural steel required can be quite extensive. Typically, it also requires that a worker atop a container on the vehicle place a spout within one of several hatches on the container and wait there until the volume of the container below the spout fills with material. Then flow to the spout is stopped, the spout is moved to an adjacent hatch and flow restarted. This process is repeated until the region below each spout is filled. Sometimes the vehicle is vibrated to assure that the spout it not merely producing a mound of material beneath each hatch, which would result in a large unused volume within the container.
Movement of the spout is either performed manually by the worker atop the vehicle, or the entire vehicle is moved and the worker will guide the spout to its final alignment. In either case, the prior art loading procedure is time consuming, and the worker is at considerable risk of an accident during the extended period of time he is atop the vehicle.
While there are several patented systems for filling multiple containers which use air streams to move light granular material, these existing systems depend upon specially designed containers and cannot be used with conventional vehicles.
For instance, U.S. Pat. No. 4,082,364 to Krambrock fills several containers in series in an air flow path, but each container is permanently piped into the air flow path and has a special internal structure. Similarly, U.S. Pat. No. 1,844,642 to Dornbrook uses specially constructed containers with internal sensors which initiate the operation of a valve within the piping to switch over from the filling of one container to another.
The present invention eliminates the requirement for special containers, and permits automatic filling of a single container with several hatches, or multiple containers located adjacent to each other, such as several hopper cars already coupled together. Moreover, this is accomplished with no reorientation of the filling spout or the vehicle itself.
To accomplish this, the present invention uses a distribution pipe with multiple fill spouts which can each be placed into a different loading hatch of one or more containers. Therefore, placement of spouts into hatches is required only once, at which time unused spouts are closed off with respect to the supply container by a diverter valve and operating spouts are opened. Subsequent to this initial set up, all control of the loading procedure is automatic.
The loading system of the preferred embodiment of the invention includes a supply container which is the source of the granular material to be loaded. This material source can be either a storage bin or a piece of processing equipment, such as a blender. The supply container feeds material into an airstream within a pipeline for delivery to the distribution pipe. Material is fed into the airstream through an airlock or some other conventional device to prevent loss of air pressure through the supply container.
The distribution pipe, which may be a rigid pipe, oriented approximately horizontally, with multiple flexible air tight fill spouts attached to it. Each fill spout extends vertically down from the distribution pipe and is selected to be long enough to extend into any container which is intended to be filled. Each fill spout is attached to the distribution pipe at a valve which can direct the air flow and, consequently, the material flow, either into the fill spout or into the downstream portion of the distribution pipe.
The valves are conventional power operated valves which simply switch the air flow to one or the other of two paths, but each is controlled by a pressure sensor located in its associated fill spout, near the input of the spout. It is the control of the valve by the pressure sensor which gives the preferred embodiment of the invention its automatic control feature.
In operation, when a valve is open to a particular fill spout, and therefore closed with respect to the remaining spouts downstream from the one which is open, the material being transferred is directed through the open spout into the container in which the spout had previously been placed. However, as the container becomes full, the material obstructs, initially very slightly, the fill spout which is the source of material, and the air pressure within the fill spout increases. It is this increase in pressure which, when it reaches a predetermined level, activates the pressure sensor within the fill spout and causes the valve at the input of the spout to change its position.
As the valve closes the fill spout associated therewith and opens the downstream section of the distribution pipe, the material flows past the now full container and proceeds to the next open fill spout, where it begins the loading procedure for that spout. The container for the new spout will then also be filled and automatically topped off before its associated valve will close its spout and continue the procedure to the next open fill spout.
To set up this action, that is, to program the procedure, it is only necessary for the operator to open the valve relative to each fill spout which will be utilized as that fill spout is being located within a container hatch. In a typical installation, there are multiple fill spouts, some of which will not be used, but regardless of whether a fill spout is at the end of the distribution pipe or between two open spouts, all that is required if it is not in use is that it be closed off by its valve. By "closed off", it is meant that the valve is placed in a "through" position whereby material will flow through the valve, into the downstream portion of the distribution pipe and into the next open fill spout, for which the valve associated therewith will be in the "divert" position. Once a fill spout is closed by its valve switching to the through position, the pressure sensor and power operation of the valve are disabled.
In normal operation, the distribution pipe is stored with all the fill spouts closed off by having the valves associated therewith placed in the through position, and the operator opens only those fill spouts, by placing the valves associated therewith in the "divert" position, which are put into use. Then each fill spout automatically closes as its container fills up and the filling of containers automatically progresses from the one nearest to the material source to the one most remote from the material source. When the loading is complete, all the valves may be placed in the through position to purge the system of excess material, and the system can be held for future use.
In an alternate embodiment of the invention, each fill spout has an associated air spreader head to distribute the material throughout the container which receives it. The spreader head is constructed with a central air supply pipe exit above a plate whose edges are curled upward to form a saucer. An inverted conical top is located above the pipe exit and covers all but the curled edges of the saucer, so that the lower edge of the cone and the saucer edge form an annular nozzle from which a stream of air acts upon the material falling down the slope of the cone. Two bolts are threaded through the saucer and support the cone so that the space between the cone and saucer edges is adjustable to control the air volume and velocity.
This addition to the loading system assures that the volume of each container is fully utilized, and its use will not hinder the pressure sensing or valve control features of the fill spouts.
The invention therefore furnishes an automatic loading system for multiple standard containers which, while assuring that each container is truly filled, nevertheless requires operator action only to initiate the filling process. Additionally, the use of structural stell necessary to complete the process can be reduced significantly. Moreover, since conventional hoisting machinery can be used to lift the distribution pipe and thus remove the closed spouts from their containers, the present invention requires no reorientation or movement of any fill spouts after the initial set up.